Numerical study of the effects of reactor geometry on a chlorine plasma helicon etch reactor

The flow field inside a helicon plasma etch reactor is simulated using a direct-simulation Monte Carlo method for a chlorine feed gas flow. Computations for the gas discharge are carried out modeling the ions and neutrals as particles and imposing the electrons as a background condition conforming to experimental measurements. The neutrals and ions are then allowed to interact with the background electrons and relax to a steady state. The resulting plasma is primarily composed of chlorine atoms and ions. The plasma flow is compared for three separate nozzle locations. The flow field, in the presence of the plasma, is found to be affected minimally by the nozzle location. A nozzle location is identified which maximizes flux to the wafer.